Energy balance following diets of varying fat content: metabolic dysregulation in a rodent model of spinal cord contusion

Within the spinal cord injured (SCI) population, metabolic dysfunction may be exacerbated. Models of cord injury coupled with metabolic stressors have translational relevance to understand disease progression in this population. In the present study, we used a rat model of thoracic SCI at level T10 (tSCI) and administered diets comprised of either 9% or 40% butterfat to create a unique model system to understand the physiology of weight regulation following cord injury. SCI rats that recovered on chow for 28 days had reduced body mass, lean mass, and reduced fat mass but no differences in percentage of lean or fat mass composition. Following 12 weeks on either low‐fat diet (LFD) or high‐fat diet (HFD), SCI rats maintained on LFD did not gain weight at the same rate as SCI animals maintained on HFD. LFD‐SCI had reduced feed conversion efficiency in comparison to Sham‐LFD whereas tSCI‐HFD were equivalent to Sham‐HFD rats. Although SCI rats still maintained lower lean body mass, by the end of the study HFD‐fed rats had higher body fat percentage than LFD‐fed rats. Macronutrient selection testing demonstrated SCI rats had a significant preference for protein over Sham rats. Analysis of metabolic cage activity showed tSCI rats had elevated energy expenditure, despite reduced locomotor activity. Muscle triglycerides and cholesterol were reduced only in LFD‐tSCI rats. These data suggest that consumption of HFD by tSCI rats alters the trajectory of metabolic dysfunction in the context of spinal cord disease progression.